Schyns G, Buckner C M, Moran C P
Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
J Bacteriol. 1997 Sep;179(17):5605-8. doi: 10.1128/jb.179.17.5605-5608.1997.
Bacillus subtilis Spo0A activates transcription from both sigmaA- and sigmaH-dependent promoters. Baldus et al. (2) identified two amino acid substitutions in the carboxyl terminus of sigmaA, K356E and H359R, that specifically impaired Spo0A-activated transcription in vivo. To test the model in which the K356E and H359R substitutions in sigmaA interfere with the interaction of Spo0A and sigmaA, we examined the effects of alanine substitutions at these positions in sigmaA on sigmaA's ability to direct transcription in vivo and in vitro. We found that alanine substitutions at these positions specifically reduced expression from the sigmaA-dependent, Spo0A-dependent promoters, spoIIG and spoIIE, in vivo. Furthermore, we found that stimulation of spoIIG promoter activity by Spo0A in vitro was reduced by the single substitutions H359A and H359R in sigmaA.
枯草芽孢杆菌Spo0A可激活依赖于σA和σH的启动子的转录。Baldus等人（2）在σA的羧基末端鉴定出两个氨基酸替换，即K356E和H359R，它们在体内特异性地损害了Spo0A激活的转录。为了测试σA中的K356E和H359R替换干扰Spo0A与σA相互作用的模型，我们研究了σA中这些位置的丙氨酸替换对σA在体内和体外指导转录能力的影响。我们发现，这些位置的丙氨酸替换在体内特异性地降低了依赖于σA、Spo0A的启动子spoIIG和spoIIE的表达。此外，我们发现，σA中的单替换H359A和H359R降低了体外Spo0A对spoIIG启动子活性的刺激。
